PharmAthene Completes Pharmacokinetic Studies of Protexia; Program
on Target for IND Filing in 2008

ANNAPOLIS, Md., March 6, 2008 /PRNewswire-FirstCall/ --
PharmAthene, Inc., a biodefense company specializing in the
development and commercialization of medical countermeasures
against chemical and biological threats, announced today that it
has completed the initial pharmacokinetic (PK) testing of
Protexia(R), the Company's broad spectrum chemical nerve agent
prophylaxis.

The PK studies were conducted in two animal species and used the
final pegylated version of rBChE for the first time. In general,
the conjugation of proteins with polyethylene glycol (PEG) has been
shown to decrease immunogenicity, increase circulating serum
half-life and increase stability of recombinant proteins. The data
from these studies confirm that the specific PEG chosen for
conjugation to rBChE will significantly improve the half-life of
the protein in vivo.

The PK studies demonstrated that Protexia(R) had a half life of
approximately four days in primates and three days in rodents when
administered by intramuscular injection. These data compare
favorably with what was predicted for the drug's PK profile in
these animal species.

John Troyer, Ph.D., Senior Program Director for Protexia(R),
commented, "These results are very meaningful in that they show
that Protexia(R) meets or exceeds our target product profile for
use as a chemical nerve agent prophylaxis. The impressive half life
data also confirm that the pegylation of rBChE as part of our
manufacturing process achieved the goal of extending the half-life
of the protein to one which makes it a feasible product for use in
humans."

Dr. Troyer continued, "Having successfully completed the PK
studies, we are on target to complete our toxicology studies and
file the Investigational New Drug (IND) application for Protexia(R)
in the third quarter of 2008; we expect to commence Phase I human
safety testing of Protexia(R) in the fourth quarter."

"Today's announcement highlights the intense commitment and
strong technical capability PharmAthene has continually
demonstrated in our attempts to rapidly progress our biodefense
product portfolio. Since acquiring Protexia(R), we have defined a
viable manufacturing process for commercial scale production and
demonstrated proof of concept showing protection with Protexia(R)
against highly lethal doses of nerve agent exposure," said David P.
Wright, President and Chief Executive Officer.

"Our proven internal expertise in drug development, in
combination with the funding and partnership provided under our DoD
contract, will significantly enhance our ability to ensure that
Protexia(R) becomes an important part of the nation's military and
civilian biodefense arsenal," continued Mr. Wright.

In September 2006, PharmAthene was awarded a multi-year contract
from the Department of Defense (DoD) U.S. Army Space and Missile
Command valued at up to $213 million assuming all extensions and
options are exercised by the DoD, for advanced development of the
Company's broad spectrum chemical nerve agent prophylaxis,
Protexia(R). The contract includes a procurement option by the DoD
for an initial 90,000 doses of Protexia(R). The Protexia(R)
contract was awarded through a full and open competitive
solicitation seeking novel second generation prophylactic products
for use in humans to prevent and treat poisoning from
organophosphorus (OP) nerve agents such as sarin gas, soman, tabun
and VX.

Protexia(R) is a form of recombinant human butyrylcholinesterase
(rBChE), a potent organophosphorus (OP) scavenger protein produced
in the milk of transgenic goats, which is being developed for use
as a prophylactic against acute organophosphorus (OP) nerve agent
toxicity.

About Chemical Weapons

Organophosphorus nerve agents, or anti-cholinesterase agents,
were discovered in the 1930s following intensive research into new
insecticides. Their discovery represents the beginning of modern
chemical warfare. These agents cause toxicity by binding to and
inhibiting acetylcholinesterase, an enzyme in the body that is
essential for nervous system function, leading to increases in
acetylcholine and "cholinergic crisis" that can cause loss of
muscle control, respiratory failure, paralysis, convulsions,
permanent brain damage and eventually death.

These so-called nerve gases, which are actually all liquids at
room temperature, are lethal far more quickly and in far lower
concentrations than other classical chemical warfare agents such as
vesicants, choking agents and blood agents, and are effective both
when inhaled and when absorbed through the skin. Nerve agents can
be classified as either G-agents (sarin, soman, tabun) or V-agents
(VX), both of which are exceedingly toxic.

About PharmAthene, Inc.

PharmAthene was formed to meet the critical needs of the United
States and its allies by developing and commercializing medical
countermeasures against biological and chemical weapons.
PharmAthene's lead programs include Valortim(TM) for the prevention
and treatment of anthrax infection and Protexia(R) for the
prevention and treatment of morbidity and mortality associated with
exposure to chemical nerve agents. For more information on
PharmAthene, please visit www.PharmAthene.com.

Statement on Cautionary Factors

Except for the historical information presented herein, matters
discussed may constitute forward-looking statements within the
meaning of the Private Securities Litigation Reform Act of 1995
that are subject to certain risks and uncertainties that could
cause actual results to differ materially from any future results,
performance or achievements expressed or implied by such
statements. Statements that are not historical facts, including
statements preceded by, followed by, or that include the words
"potential"; "believe"; "anticipate"; "intend"; "plan"; "expect";
"estimate"; "could"; "may"; "should"; "could"; or similar
statements are forward-looking statements. PharmAthene disclaims,
however, any intent or obligation to update these forward-looking
statements. Risks and uncertainties include risk associated with
the reliability of the results of the studies relating to human
safety and possible adverse effects resulting from the
administration of Protexia(R), unexpected funding delays,
unforeseen safety issues, unexpected determination that Protexia(R)
proves not to be effective or capable of being marketed as a
product, as well as risks detailed from time to time in
PharmAthene's public disclosure filings with the U.S. Securities
and Exchange Commission (the "SEC"). There can be no assurance that
such development efforts will succeed or that other developed
products will receive required regulatory clearance, or that, even
if such regulatory clearance were received, such products would
ultimately achieve commercial success. Copies of PharmAthene's
public disclosure filings are available from its investor relations
department.